General term Tr+1=9Cr((3x22))r((−13x))9−r=9Cr((32))rx2r((−13))9−r((1x))9−r=9Cr((32))r((−13))9−rx2rxr−9=9Cr((32))r((−13))9−rx3r−9
as we need term independent of x
∴x3r−9=x0or3r−9=0∴r=3∴term=T3+1=t4(4thterm)